🔄 Torque & Rotational Motion — Unit Quiz

A force of 15 N is applied perpendicular to the end of a 0.4 m wrench. What torque is produced about the bolt?

At what angle between the applied force and the lever arm is the torque maximized?

A figure skater spins with arms outstretched, then pulls her arms tightly against her body. Her angular velocity:

A see-saw is balanced at its center pivot. A 40 kg child sits 2 m to the left. How far to the right must an 80 kg adult sit to balance the see-saw? (g = 10 m/s²)

A uniform beam rests horizontally in static equilibrium supported at both ends. Select ALL conditions that must be satisfied.

A force of 24 N is applied to the end of a 0.6 m lever arm at 30° from the lever arm direction. What is the resulting torque?

A torque of 30 N·m acts on an object with rotational inertia I = 6 kg·m². What is the angular acceleration?

A 4 m uniform plank (mass 10 kg) rests on supports at both ends. A 30 kg box sits 1 m from the left end. What is the upward force from the RIGHT support? (g = 10 m/s²)

A solid disk (mass M, radius R) and a hoop (mass M, radius R) are compared. Which has the greater rotational inertia about the central axis?

Select ALL correct analogies between translational and rotational motion.

A 4 m horizontal beam (mass 12 kg) is hinged to a wall at its left end. A wire at the right end makes 53° with the beam (sin 53° = 0.8). A 24 kg block hangs from the right end. What is the tension T in the wire? (g = 10 m/s²)

A solid disk (I = ½MR²) and a hoop (I = MR²) of equal mass and radius are released simultaneously from rest at the top of an inclined plane and roll without slipping. Which reaches the bottom first?

A spinning top gradually slows down due to friction with the floor. Select ALL correct statements.

A 6 m uniform horizontal beam (mass 20 kg) is hinged to a wall at its left end. A support wire is attached at the right end, angling up to the wall at 37° above horizontal (sin 37° = 0.6, cos 37° = 0.8). A 50 kg sign hangs from the right end. (g = 10 m/s²) (a) Calculate the tension in the wire. (b) Find the horizontal and vertical components of the hinge force.

A student opens a door by pushing perpendicularly with 15 N at 80 cm from the hinge. The door has rotational inertia I = 2.5 kg·m² about the hinge. Starting from rest: (a) Find the angular acceleration. (b) Find the angular velocity after the door has rotated 90° (π/2 rad). (c) Find the rotational kinetic energy at that point.